I kinda agree. Simply saying that his reaction time was shit from living a relaxed lazy life (which he does kinda say after the bullshit reason) would have been a better less ass pully reason why that point bland attack worked.
"I have taken your power. I doubt we will ever meet again. Farewell." Narrator: The protagonist will, in fact, meet him again and lament his past decisions.
Ffs, I'm tired of this shit. I hope this won't happen.